Answer:
B. use file compression
Step-by-step explanation:
One way to improve the storage capacity of a hard disk is to use file compression.
File compression is a technique that reduces the size of a file by removing redundant or unnecessary data. By using file compression, you can reduce the size of a file and free up space on the hard disk. This can be particularly useful for large files or for files that are not frequently accessed, as they can be compressed and stored more efficiently on the hard disk.
The other options provided in the question are not effective ways to improve the storage capacity of a hard disk. Formatting a hard disk often will not increase its storage capacity, as formatting simply erases the data on the disk and does not change the size of the disk itself. Increasing the memory of a computer will not affect the storage capacity of the hard disk, as the memory and the hard disk are separate components. Disk caching is a technique that improves the performance of a hard disk by storing frequently accessed data in memory, but it does not increase the storage capacity of the disk.
Therefore, the correct answer is:
B. use file compression.